• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.463-473
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• 2021

Recently, United States Geological Survey (USGS) distributed Landsat 8 Collection 2 Level 2 Science Product (L2SP). This paper aims to derive land surface temperature from L2SP and to validate it. Validation is made by comparing the land surface temperature with the one calculated from Landsat 8 Collection 1 Level 1 Terrain Precision (L1TP) and the one from Automated Synoptic Observing System (ASOS). L2SP is calculated from Landsat 8 Collection 2 Level 1 data and it provides land surface temperature to users without processing surface reflectance data. Landsat 8 data from 2018 to 2020 is collected and ground sensor data from eight sites of ASOS are used to evaluate L2SP land surface temperature data. To compare ground sensor data with remotely sensed data, 3×3 grid area data near ASOS station is used. As a result of analysis with ASOS data, L2SP and L1TP land surface temperature shows Pearson correlation coefficient of 0.971 and 0.964, respectively. RMSE (Root Mean Square Error) of two results with ASOS data is 4.029℃, 5.247℃ respectively. This result suggests that L2SP data is more adequate to acquire land surface temperature than L1TP. If seasonal difference and geometric features such as slope are considered, the result would improve.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.699-707
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• 2021

Hwajinpo Lagoon, located on the eastern coast of Korea, is a unique environment where freshwater and saltwater are mixed. Systematic management of the lagoon is required because it is a biodiversity-rich and area of high conservation value. The existing environment of the lagoon was evaluated by identifying the distribution of the groundwater level and groundwater flow characteristics. In addition, hydrogeochemical fluctuations were analyzed to determine the effect of seawater intrusion into the aquifer. The results demonstrate that the freshwater-saltwater interface is distributed throughout the aquifer and rises when water of the lagoon evaporates due to prolonged periods of low rainfall and high temperature, thereby increasing the possibility of seawater inflow through groundwater. As for the ionic delta properties (difference between the measured and theoretical concentration of mixed waters), it was estimated that the cation-exchange and precipitation reactions occurred in the aquifer due to seawater intrusion. The ratio of seawater mixed at each point was calculated, using oxygen isotopes and chloride as tracers, resulting in an average of 0.3 and a maximum of 0.87. The overall seawater mixing ratio appears to be distributed according to the distance from the coast. However, some of the results were deviated from the theoretical expectations and reflected the characteristics of the nearby aquifers. Further research on seasonal changes and simulation of seawater intrusion mechanisms is required for specific analysis.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.559-575
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• 2021

Due to the increase in ground excavation work, the possibility of ground subsidence accidents is increasing. And it is very difficult to prevent these risk fundamentally through institutional reinforcement such as the special law for underground safety management. As for the various cases of urban ground excavation practice, the ground subsidence behavior characteristics which is predicted using various information before excavation showed a considerable difference that could not be ignored compared to the results real construction data. Changes in site conditions such as seasonal differences in design and construction period, changes in construction methods depending on the site conditions and long-term construction suspension due to various reasons could be considered as the main causes. As the countermeasures, the safety management system through various construction information is introduced, but there is still no suitable system which can predict the effect of excavation and risk assessment. In this study, a web-based system was developed in order to predict the degree of impact on the ground subsidence and surrounding structures in advance before ground excavation and evaluate the risk in the design and construction of urban ground excavation projects. A system was built using time series analysis technique that can predict the current and future behavior characteristics such as ground water level and settlement based on past field construction records with field monitoring data. It was presented as a geotechnical data visualization (GDV) technology for risk reduction and disaster management based on web-based system, Using this newly developed web-based assessment system, it is possible to predict ground excavation impact prediction and risk assessment.

• Journal of Marine Life Science
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• v.4 no.2
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• pp.53-62
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• 2019

Heterotrophic bacteria are a major member of the microbial loop in the marine ecosystem and play an important role in the biogeochemical cycle decomposing organic matter. Therefore study of bacterial variation is important to understand the material cycle and energy flow of marine ecosystems. We investigated the monthly variations of bacteria and environmental factors in the Youngsan River estuary, and the correlation between bacteria and phytoplankton biomass (chlorophyll-a) including size-structure. As a result, bacteria of the Youngsan River estuary were higher in the surface than in the bottom layer, and higher in the summer than in winter. And the closer to the dike, the abundance increased, and it increased to the peaks in August, September, and June 2019 at the station closest to the dike. The chlorophyll-a also increases at the stations and time when the bacterial abundance was high and they correlates positively displaying no difference between size fractions. The results indicate that organic matter derived from phytoplankton has an effect on bacterial variation but no size-dependent effects. In addition, the seasonal pattern of bacteria increasing in proportion to the water temperature suggests the effect of water temperature on the growth of bacteria. No association of bacterial abundance variation with nutrient supply due to freshwater input was observed. In this study, dissolved oxygen was depleted and hypoxia was observed for a short time when a strong stratification was not developed. This may be resulted from the supply of organic matter from phytoplankton and the consumption of oxygen due to bacterial decomposition.

• Journal of Korea Water Resources Association
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• v.55 no.spc1
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• pp.1283-1293
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• 2022

The purpose of this study is to predict residual chlorine in order to maintain stable residual chlorine concentration in sedimentation basin by using artificial intelligence algorithms in water treatment process employing pre-chlorination. Available water quantity and quality data are collected and analyzed statistically to apply into mathematical multiple regression and artificial intelligence models including multi-layer perceptron neural network, random forest, long short term memory (LSTM) algorithms. Water temperature, turbidity, pH, conductivity, flow rate, alkalinity and pre-chlorination dosage data are used as the input parameters to develop prediction models. As results, it is presented that the random forest algorithm shows the most moderate prediction result among four cases, which are long short term memory, multi-layer perceptron, multiple regression including random forest. Especially, it is result that the multiple regression model can not represent the residual chlorine with the input parameters which varies independently with seasonal change, numerical scale and dimension difference between quantity and quality. For this reason, random forest model is more appropriate for predict water qualities than other algorithms, which is classified into decision tree type algorithm. Also, it is expected that real time prediction by artificial intelligence models can play role of the stable operation of residual chlorine in water treatment plant including pre-chlorination process.

• Korean Journal of Ichthyology
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• v.34 no.3
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• pp.201-207
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• 2022

Total 418 Yellow Croaker Larimichthys polyactis were examined and the range of total length (TL) was 12.0~27.5 cm and average total length was 19.6 cm. The most important prey component in the diets of L. polyactis was Pisces that constituted 46.5% in %IRI (Index of relative importance). Euphausiacea was the second largest prey component. The result of analysis in ontogenetic and seasonal changes significantly exhibited. The proportion of Pisces increased as increasing body size, whereas the consumption of Macrura decreased gradually. The diets also were different among seasons, with the difference particularly being evident between warm (summer and autumn) and cold (winter and spring) seasons. Permutational multivariate analysis of variance (PERMANOVA) revealed significant dietary differences by seasons (P=0.001).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.1
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• pp.1-10
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• 2006

Previous studies on zooplankton in Asan Bay were mostly based on samples collected seasonally with three months intervals. Present study was aimed to know the temporal variation of meso-zooplankton distribution using the data collected monthly. Relationships between zooplankton abundances and environmental factors such as seawater temperatures, salinities and chlorophyll-a contents were also studied. Seawater temperature showed typical pattern of seasonal variation found in temperate waters. The fluctuations of environmental factors ranged relatively wider In the inner part of the bay than those in outer part of the bay. Salinity was very low right after the summer rainy period due to the sporadic outflow of freshwater from the adjacent artificial lakes. Sudden changes in salinity seemed to have significant impact on zooplankton assemblages. Chlorophyll-a contents were increased in general when compared with previous reports probably due to the recent human exploitations in the coastal zone, which might enhance the nutrients level . The timing and duration of spring bloom showed geographical differences. In the inner part of the bay it began earlier (February) and last longer (three months) while in the outer part of the bay it began late (April) and last just one month. Zooplankton abundance, especially most abundant taxon Acartia hongi, showed weak but significant positive correlation with chlorophyll-a contents. The difference in temporal variation found with two different sampling intervals indicated the necessity of shorter time interval samplings.

• Journal of Korean Medical classics
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• v.37 no.2
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• pp.49-76
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• 2024

Objectives : The purpose of this paper is to examine the mechanism and treatment of the Zangfu warm disease in the Beijiqianjinyaofang. Methods : This study examined the Zangfu warm disease content in the Beijiqianjinyaofang, Shanghanzongbinglun, Saninfang, based on the Neijing explanation of the pathological mechanism. Treatment was analyzed among the three texts in terms of their similarity and difference. Results & Conclusions : 1. Zangfu warm disease is caused by seasonally inappropriate qi, which is infectious, epidemic, and seasonal. 2. While the Qingjinqian disease pattern was explained in terms of the relationship between Shaoyin and Shaoyang, the actual disease pattern happened more in the Taiyang channel, and partly in the Shaoyang channel. For treatment of Fu deficiency pattern, the Chaihudihuangtang was listed in the Qianjinyaofang and the Shanghanzongbinglun, while in the Sanyinfang, the formula was modified to extinguish heat and thin phlegm, while reinforcing healthy qi. 3. The Chimaifei disease pattern was explained in terms of the relationship between Shaoyin and Taiyang that is deeply associated with Wei qi. For treatment of Fu deficiency the Qianjinyaofang and Shanghanzongbinglun used the Shigaodihuangtang, while the Sanyinfang reinforced healthy qi and eliminated pathogenic qi. 4. The Huangrousui disease pattern was explained as being caused by problems in the Taiyin and Yangming, in which the Triple Burner fails to control and manage cold dampness. In treating Zang excessiveness, the Qianjinyaofang and Shanghanzongbinglun used the Xuanshenhanshuishitang, while the Sanyinfang instructed to reinforce healthy qi and eliminate pathogenic qi. In treating Fu deficiency, the Sanyinfang instructed to warm the center and dry dampness, tonifying the Spleen and reinforcing qi. 5. The Baiqili disease pattern was explained within the relationship between Taiyin and Taiyang. In treating Fu deficiency, the Qianjinyaofang and Shanghanzongbinglun used the Shigaoxingrentang, while the Sanyinfang instructed to reinforce healthy qi and eliminate pathogenic qi. In treating Zang excessiveness, the Qianjinyaofang and Shanghanzongbinglun used the Shigaocongbaitang, while the Sanyinfang instructed to reinforce healthy qi and eliminate pathogenic qi. 6. The Heiguwen disease pattern was explained as being caused by stagnation and obstruction in the Triple Burner due to clash between Taiyang and Shaoyin. In treating Zang excessiveness, the Qianjinyaofang and Shanghanzongbinglun used the Kushenshigaotang, while the Sanyinfang instructed to reinforce healthy qi and eliminate pathogenic qi. The Zangfu Warm Disease is a infectious disease concept which is based on the Five Zang that integrates the meridian aspect together with the Six Fu with which there is an external/internal relationship. This concept and treatment could be considered in dealing with COVID-19.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.182-187
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• 2024

Feeding habits of the large yellow croaker, Larimichthys crocea, was studied using 816 specimens collected by large pair-trawl fishery from June 2021 to May 2022 in the coastal waters of Jeju Island, Korea. The range of total length was 19.8~57.4 cm. Using the IRI, Pisces were mainly prey component constituted 57.5%. Euphausiacea and Macrura were important prey component constituted 23.2% and 18.7%, respectively. There was a significant difference in the change in diet composition by size group. As the L. crocea grew, the feeding rate of Euphausiacea decreased and the feeding rate of Pisces increased. There were also significant differences in the changes in diet composition by seasonal group. The most important prey species for L. crocea in the winter and spring were Pisces, in the summer it was Macrura, and in the fall it was Euphausiacea. As a result of analyzing the feeding relationship between size groups and season groups, L. crocea showed significant differences in the interaction between size groups and season groups.

• Particle and aerosol research
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• v.19 no.4
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• pp.129-144
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• 2023

The PM_1.0 and PM_2.5 samples were collected synchronously using a single channel particulate sampler equipped with PM_1.0 and PM_2.5 cyclones, respectively, and seasonal mass concentration and chemical composition of PM_1.0 and PM_2.5 were quantified in Seoul and Gwangju in 2021-2022. The mass concentrations of PM_1.0 and PM_2.5 were 17±11 and 22±14 ㎍/m³ in Seoul, and 16±9 and 19±12 ㎍/m³ in Gwangju, respectively. The average ratios of PM_1.0/PM_2.5 were 83±16% in Seoul and 83±7% in Gwangju. The chemical compositions of PM_1.0 and PM_2.5 were similar at both sites with OC component being the most dominant, and NO₃^- increasing from summer to winter, while, the difference of chemical distribution at the two sites was most distinct in the autumn. Gwangju showed a higher proportion of OC and a lower proportion of NO₃^- compared to Seoul during the autumn. Both sites appear to reflect their urban characteristics, with Gwangju also reflecting the impact of biomass combustion as a part of rural activities.